Field of the Invention
The present invention relates to a display device, and more particularly, to a display device with integrated touch screen.
Discussion of the Related Art
With the advancement of information-oriented society, various requirements for display field are increasing. Recently, various display devices, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), organic light emitting display devices, etc., are being used.
Such display devices use a touch-based input method which enables a user to easily, intuitively, conveniently input information or a command, instead of a general input method using a button, a keyboard, or a mouse.
In order to provide the touch-based input method, it is required to determine the presence of a user's touch and accurately detect touch coordinates.
To this end, in the related art, a touch sensing function is provided by using one of various touch types such as a resistive type, a capacitance type, an electromagnetic induction type, an infrared type, and an ultrasound type. In the capacitance type, a mutual capacitance type that uses a mutual capacitance between a plurality of touch electrodes (for example, longitudinal electrodes and horizontal electrodes) provided in a touch screen panel or a self-capacitance type that detects the presence of a touch and touch coordinates based on a capacitance change between pointers such as a touch electrode and a finger is widely used.
In various touch types, a touch driving mode may be divided into an idle mode for determining whether there is a touch input and an active touch mode for detecting a touch input position. That is, a panel is driven in the idle mode for determining whether the panel is touched, and when a touch input occurs while the idle mode is being executed, the panel is driven in the active touch mode for detecting a touch input position.
However, in general touch screens, there is no driving difference between the idle mode and the active mode in a touch type, and for this reason, power is unnecessarily consumed because a touch operation of a panel is performed even in the idle mode identically to the active touch mode.
Hereinafter, the above-described problem will be described with reference to FIGS. 1 and 2.
FIG. 1 is a diagram illustrating an application of a touch scan signal in an idle mode and an active mode in a general touch screen display device.
In the general touch screen display device, as illustrated in FIG. 1, the touch scan signal is continuously applied through an ROIC in a touch active driving mode and a touch idle driving mode.
To provide a more detailed description on driving of FIG. 1, electrodes #1 to #6 may be sensed a total of two times in the touch active driving mode. In other words, in an example of FIG. 1, the touch scan signal is applied to all electrodes a total of two times in the touch active driving mode during one frame period. In the touch idle driving mode, the electrodes #1 to #6 may be sensed once. In other words, in the example of FIG. 1, the touch scan signal is applied to all the electrodes once in the touch idle driving mode during one frame period.
As described above, unlike the touch active driving mode, in the touch idle driving mode, a method is used in which the number of times the panel is wholly sensed is reduced by lowering a frequency at which the touch scan signal is applied, and the ROIC is always turned on even in the touch idle driving mode. For this reason, even when the touch idle mode is continuously executed, consumption power is not reduced.
FIG. 2 is a diagram illustrating an application of a touch scan signal in an idle mode and an active mode in a general display device with integrated touch screen.
The display device with integrated touch screen includes an in-cell type touch screen, and a display driving operation and a touch driving operation are time-division performed during one frame. For such driving, a common electrode which is used for display driving is used as a touch electrode in a touch driving period.
Referring to FIG. 2, in the general display device with integrated touch screen, a touch scan signal is continuously applied through ROIC in a touch driving mode including the touch active driving mode and the touch idle driving mode.
In other words, FIG. 2 illustrates an example of the general display device with integrated touch screen. As described above, a display driving operation and a touch driving operation are time-division performed during one frame, and thus, the touch scan signal is continuously applied through the ROIC in the touch driving mode except the display driving mode.
To provide a more detailed description on driving of FIG. 2, electrodes #1 to #6 may be sensed a total of two times in the touch active driving mode included in the touch driving mode. In other words, in an example of FIG. 2, the touch scan signal is applied to all electrodes a total of two times in the touch active driving mode during one frame period. In the touch idle driving mode, the electrodes #1 to #3 may be sensed a total of two times in the touch idle driving mode. Alternatively, in the touch idle driving mode, the electrodes #1 to #3 may be sensed once, and the electrodes #4 to #6 may be sensed once.
As described above, unlike the touch active driving mode, in the touch idle driving mode, a method is used in which the number of times the panel is wholly sensed is reduced by lowering a frequency at which the touch scan signal is applied, and the ROIC is always turned on even in the touch idle driving mode identically to the touch active driving mode. For this reason, in the touch driving mode of an in-cell type touch screen according to an example of FIG. 2, even when the touch idle mode is continuously executed, consumption power is not reduced.